2 Die in Sweat Lodge at Ariz. Retreat

Two people died and an estimated 19 others were taken to hospitals after being overcome while sitting in a sauna-like sweat lodge during a Sedona spiritual retreat, authorities said Friday.

Sixty-four people were in a crudely constructed sweat dome at the 70-acre Angel Valley resort Thursday evening, Yavapai County sheriff's spokesman Dwight D'Evelyn said. The resort nestled in the forest about 20 minutes from Sedona, a resort town about 115 miles north of Phoenix that is well-known as a center for the New Age spiritual movement.

The resort is not far from Sen. John McCain's ranch, reports CBS affiliate KPHO in Phoenix.

Many people began feeling ill after about two hours in the sweat box, emerging lightheaded and weak, said Verde Valley Fire District Chief Jerry Doerksen. Authorities haven't determined the cause of the deaths and illnesses; tests for carbon monoxide and other contaminants were negative. D'Evelyn said authorities were checking into whether any of the attendees had pre-existing medical conditions and the possibility that some of the people might have been fasting.

About 21 people were taken by ambulance or helicopter to area hospitals, where two were pronounced dead, D'Evelyn said. The dead were identified only as a man and woman, both middle-aged.

Three people taken to Flagstaff Medical Center were listed in critical condition Friday, and another was in fair condition. Three others who were admitted to a hospital in nearby Verde Valley recovered quickly; two of them were released overnight and one was reported in good condition Friday.

Sheriff's homicide investigators were working to determine what happened and whether any criminal actions might have been a factor in the incident, D'Evelyn said. Investigators were at the resort Friday interviewing the retreat director, staff and guests, including some who told detectives they paid up to $9,000 for the multi-day program.

A woman who answered the phone at the resort Friday said its founders, Michael and Amayra Hamilton, would have no comment. A call to the Hamilton's home went unanswered.

The owners are also ordained ministers, KPHO's Sarah Buduson reports.

Authorities said self-help expert and author James Arthur Ray rented the facility and was hosting the group inside the dome, a low-lying structure covered with tarps and blankets. In a testimonial on the retreat's Web site, Ray said it "offers an ideal environment for my teachings and our participants."

Ray's company, James Ray International, is based in Carlsbad, California.

A spokesman for Ray, Howard Bragman, confirmed that Ray was holding an event at the retreat, as he has done in the past.

Doerksen, whose fire district responded to emergency calls, said he sent a hazardous materials team into the sweat lodge to test for carbon monoxide, carbon dioxide and other contaminants. The test "didn't show anything out of the ordinary," he said.

The Angel Valley Spiritual Retreat Center, built on former ranch property in the high-desert and red-rock country of northern Arizona, bills itself as a natural environment for self discovery and healing through a holistic approach aimed at balancing the mind, emotions, body and spirit.

The property includes American Indian structures such as teepees, guest houses and outdoor labyrinths made of stones.